<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>localStorage</title>
  </head>

  <body>
    <h2>localStorage</h2>
    <button onclick="saveData()">点我保存一个数据</button>
    <button onclick="readData()">点我读取一个数据</button>
    <button onclick="deleteData()">点我删除一个数据</button>
    <button onclick="clearData()">点我删除所有数据</button>
  </body>
  <script>
    let person = {
      name: "张三",
      age: 18,
    };
    function saveData() {
      localStorage.setItem("msg", "Hello!");
      localStorage.setItem("msg2", 666);
      localStorage.setItem("person", JSON.stringify(person));
    }

    function readData() {
      console.log(JSON.parse(localStorage.getItem("person")));
      console.log(JSON.parse(localStorage.getItem("person4"))); //null
    }

    function deleteData() {
      localStorage.removeItem(localStorage.removeItem("msg2"));
    }

    function clearData() {
      localStorage.clear();
    }
  </script>
</html>
